svn commit: r198853 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Tue Nov  3 12:52:35 2009
New Revision: 198853
URL: http://svn.freebsd.org/changeset/base/198853

Log:
  If socket buffer space appears to be lower then sum of count of already
  prepared bytes and next portion of transfer, inner loop of kern_sendfile()
  aborts, not preparing next mbuf for socket buffer, and not modifying
  any outer loop invariants. The thread loops in the outer loop forever.
  
  Instead of breaking from inner loop, prepare only bytes that fit into
  the socket buffer space.
  
  In collaboration with:	pho
  Reviewed by:	bz
  PR:	kern/138999
  MFC after:	2 weeks

Modified:
  head/sys/kern/uipc_syscalls.c

Modified: head/sys/kern/uipc_syscalls.c
==============================================================================
--- head/sys/kern/uipc_syscalls.c	Tue Nov  3 12:03:13 2009	(r198852)
+++ head/sys/kern/uipc_syscalls.c	Tue Nov  3 12:52:35 2009	(r198853)
@@ -2037,20 +2037,12 @@ retry_space:
 				rem = obj->un_pager.vnp.vnp_size -
 				    uap->offset - fsbytes - loopbytes;
 			xfsize = omin(rem, xfsize);
+			xfsize = omin(space - loopbytes, xfsize);
 			if (xfsize <= 0) {
 				VM_OBJECT_UNLOCK(obj);
 				done = 1;		/* all data sent */
 				break;
 			}
-			/*
-			 * Don't overflow the send buffer.
-			 * Stop here and send out what we've
-			 * already got.
-			 */
-			if (space < loopbytes + xfsize) {
-				VM_OBJECT_UNLOCK(obj);
-				break;
-			}
 
 			/*
 			 * Attempt to look up the page.  Allocate